The present invention relates to laptop computers, and in particular to wireless communication between a pointing device and a laptop computer.
A wide variety of pointing devices have been developed for personal computers. A user can hook up a mouse, trackball, joystick, or game pad, for instance. Touch pads and micro sticks are also used, although typically these are integrated into a keyboard of a laptop computer. Cordless pointing devices have been developed, to avoid the need to move a cable around with the pointing device. For example, a mouse can have a radio transmitter which transmits to a receiver plugged into an RS232 port of a computer. For desktop personal computers, a user can switch which device is plugged in depending upon the application. For a laptop, however, usually the user picks a laptop which already has integrated a particular type of pointing device with which the user is comfortable. This could either be a touchpad, microstick or trackball, for instance.
Wireless technology has also been applied in a variety of applications relating to personal computers other than between a pointing device and a receiver plugged into a personal computer. For example, a universal wireless interface between PC""s and a number of electronic devices has been proposed by Intel and others, code-name Bluetooth. In particular, a radio receiver in a personal computer would communicate with a cell phone to allow wireless e-mail, etc. The Bluetooth module includes electronics and an antenna. For a laptop computer, the computer housing is typically a shield for the electronics inside, making an integrated antenna problematic. When mounted in a notebook or laptop PC, the Bluetooth module is intended to be located on the top edge of the display, outside the shields in the computer housing.
An alternate technology to RF radio for a wireless connection is an IrDA link. This is employed in many notebooks and in the newest Pakn Pilot(trademark).
The present invention integrates an antenna for wireless communication into a touchpad module. A touchpad module, which can be inserted into an aperture in a laptop computer, includes a touch sensor for detecting a user""s touch, and a touch sensor circuit for processing signals from the touch sensor. The antenna is connected to the touchpad module.
The novel use of the touchpad for including an antenna provides an open aperture for the antenna to communicate with the outside world, without being blocked by the shielding used in a laptop computer. An advantage of using the touchpad aperture for the antenna is that it is a relatively large size opening already available in a laptop computer, which is not shielded. It also allows the antenna to be integrated into the computer without changing the form factor of the laptop computer.
In one embodiment, the touchpad module can contain a switching circuit allowing it to switch between an input from the touch sensor and the antenna. Thus, a user who is more comfortable with an external pointing device, such as a mouse, trackball, etc. can provide the input to the computer while disabling the touchpad at the same time. Alternately, both pointing devices can be active at the same time. In one embodiment some of the circuitry can be shared between the external pointing device and the touchpad module.
The antenna can be implemented in a variety of embodiments. In one embodiment, the touchpad sensor is mounted on a flex circuit, with the electronics off to the side away from the aperture, with a guard ring around the aperture being used for the antenna. In another embodiment, all of the traces on the touchpad are used for the antenna, with the computer case being ground. Alternately, an antenna dipole could be formed using different traces of a sensor array. Alternately, the whole array of traces could be used as an antenna. In yet another embodiment, the ground plane under the array of traces could be used as an antenna.
The antenna of the invention is connected to a receiver, and can also be connected to a transmitter. Such a transmitter may be used for providing force feedback. In addition, multiple devices could then wirelessly connect to the computer. For example, a mouse input could provide additional features for a joystick, or could activate a force feedback function on itself or a joystick or other device.
For further understanding of the nature and advantages of the invention, reference should be made to the following description taken in conjunction with the accompanying drawings.